Extrusion devices are used to melt, blend, and form materials into a desired shape. Typical extrusion devices include a rotating screw housed coaxially within a heated, cylindrically-shaped barrel. The screw rotates within the barrel and drives an extrusion material, such as plastic, through the barrel. The extrusion material is forced through a die or aperture at the end of the barrel.
The temperature of the extrusion material is usually controlled in the barrel to achieve a product having desired characteristics and one that has an appropriate consistency to be forced through the die.
A controller receives signals from the temperature sensors positioned in and around the barrel of the extruder at different locations along the length of the barrel. The controller determines whether the temperature of a given heat exchange zone is too cool or too hot relative to the temperature set point for that heat exchange zone. If there is a difference, the controller signals the appropriate heat exchange elements to increase or decrease the heat in the particular zone.